Nitazenes: the synthetic opioids that can be stronger than fentanyl you've never heard of
Just as public-health workers learned to reckon with fentanyl, a different family of synthetic opioids began surfacing in the drug supply — some of them even more potent, and most people have never heard the name. They are called nitazenes, and they are spreading quietly across dozens of countries.
What nitazenes are
Nitazenes are a class of synthetic opioids first synthesised in the 1950s during a search for painkillers, then shelved and never brought to market. Decades later they have re-emerged as illicit new psychoactive substances. Chemically they are distinct from fentanyl — a separate structural family — which is part of why they have been able to slip into the supply without being noticed.
How strong they are
Potency is the whole problem. Laboratory estimates place many nitazenes far above morphine in strength, and some in the range of — or exceeding — fentanyl itself. At that potency the margin between a dose and a fatal dose can be a matter of specks, and it is nearly impossible to gauge by eye in a street mixture.
A fast-moving target
The UN Office on Drugs and Crime has watched the group multiply through its early-warning system: from a single nitazene reported in 2019 to more than a dozen by 2023, with over 30 analogues since detected across dozens of countries. Isotonitazene was placed under international control in 2020, and further nitazenes have been scheduled as they appear — regulators chasing a chemistry that keeps changing shape.
Why they are hard to catch
Because nitazenes are chemically unrelated to fentanyl, they can evade tests calibrated for it — and fentanyl test strips are not designed to detect them. They do respond to naloxone, but their potency can mean an overdose requires repeated doses and sustained rescue breathing. As with xylazine, the practical lesson is that “fentanyl” is no longer the whole story of the synthetic-opioid supply, and drug checking and naloxone access matter more than ever.